[Cartridge Dust Collector]Working Principle of Cartridge Dust Collector

Introduction to Cartridge Dust Collector

Cartridge dust collectors have appeared in Japan and some European and American countries as early as the 1970s, with small size. , high efficiency, low investment, easy maintenance and other advantages, but because of its small equipment capacity, it is difficult to combine into a large air volume equipment, the filtration wind speed is low, the application range is narrow, and it is only used in food, welding and other industries, so it has not been widely used for many years. promotion. In recent years, with the continuous development of new technologies and new materials, companies in Japan and the United States have improved the structure and filter material of the dust collector, making the filter cartridge dust collector widely used in cement, steel, electricity, In food, metallurgy, chemical and other industrial fields, the overall capacity has increased several times, and it has become a large-scale dust collector (GB6719-86 category) with a filter area of > 2000m2, which is a solution to the traditional dust collectors. Compared with the existing bag type and electrostatic precipitators on the market, it has the advantages of large effective filtration area, low pressure difference, low emission, small volume and long service life. Long and other characteristics have become a new direction for the development of industrial dust collectors.

The structure of the cartridge type dust collector

The structure of the filter cartridge type dust collector is composed of the air inlet pipe, the exhaust pipe, the box, the ash hopper. , dust cleaning device, diversion device, airflow distribution plate, filter cartridge and electronic control device, similar to the air box pulse bag dust removal structure.

The arrangement of the filter cartridge in the dust collector is very important. It can be arranged vertically on the pattern board of the box, or it can be arranged obliquely on the pattern board. From the dust removal effect, the vertical arrangement is more reasonable. The lower part of the flower plate is the filter chamber, and the upper part is the air box pulse chamber. An air distribution plate is installed at the inlet of the dust collector.

The working principle of the cartridge type dust collector

After the dust-laden gas enters the dust hopper of the dust collector, due to the sudden expansion of the airflow section and the action of the airflow distribution plate, the air flow in the Part of the coarse particles settle in the ash hopper under the action of dynamic and inertial forces; after the dust particles with fine particle size and low density enter the dust filter chamber, the dust is deposited on the surface of the filter material through the combined effects of Brownian diffusion and sieving, and the purified The gas enters the clean air chamber and is discharged by the exhaust pipe through the fan.

The resistance of the cartridge type dust collector increases with the increase of the thickness of the dust layer on the surface of the filter material. When the resistance reaches a certain value, cleaning is carried out. At this time, the PLC program controls the opening and closing of the pulse valve. First, the lift valve of one sub-chamber is closed to cut off the filtered air flow, and then the electromagnetic pulse valve is opened, and the compressed air rapidly expands in the upper box in a short period of time, pouring into the filter cartridge, making the filter cartridge The expansion deformation produces vibration, and under the action of reverse airflow, the dust attached to the outer surface of the filter bag is peeled off and falls into the ash hopper. After the cleaning is completed, the electromagnetic pulse valve is closed, the poppet valve is opened, and the chamber returns to the filtering state. The cleaning of each chamber is carried out in sequence, and a cleaning cycle starts from the cleaning of the first chamber to the beginning of the next cleaning. The falling dust falls into the ash hopper and is discharged through the ash-removing valve.

During this process, the filter cartridge must be replaced and cleaned regularly to ensure the filtering effect and accuracy, because in the filtering process, in addition to being blocked, some of the dust will be deposited on the surface of the filter material, increasing the resistance, so the general correct replacement time is three to five months!

Technical Improvement Measures and Selected Technology

4.1Cleaning Device

The traditional filter cartridge dust collector has two cleaning methods, one is high-pressure airflow backflushing, and the other is pulsed airflow injection. Practice has shown that the former has the advantage of uniform airflow, and the disadvantage is large air consumption; the latter has the advantage of Is the air consumption is small, the disadvantage is that the airflow is weak. To this end, two improvements can be made: on the one hand, a diversion device is added to the pulse blowing pipe to strengthen the air induction effect; . After such improvement, the air consumption is less, the air flow is uniform, and the cleaning effect is good.

4.2Air volume distribution plate

The air distribution of the filter cartridge dust collector is very important, and it must be considered how to avoid the Higher wind speeds create areas of high wear on the filter media. The air distribution plate used in the cartridge type dust collector has unique requirements, and the air distribution must be very stable and uniform. It is conducive to the rise of airflow and the fall of dust, and the opening rate of the airflow distribution plate is 35%. According to the calculation, the resistance coefficient is less than 2, so it can be seen that the porous airflow distribution plate can meet the requirements of the filter cartridge dust collector when the airflow velocity is less than 0.8m/s.

Dust removal process

1, capture separation process

① Capture transition stage. The essence is the concentration stage of dust. The dust uniformly mixed or suspended in the carrier medium enters the dust removal space of the dust collector. Due to the action of external force, the dust is pushed to the separation interface, and as the dust moves to the separation interface, the concentration becomes larger and larger, which is further prepared for solid-gas separation.

②Separation stage. When the high-concentration dust flow flows to the separation interface, there are two mechanisms of action: first, the ability of the carrier medium to carry dust gradually reaches the limit state. Second, in the high-concentration dust flow, the diffusion and agglomeration trend of dust particles is dominated by agglomeration, and the particles can agglomerate with each other or on the substantial interface and adsorb.

2, dust removal process

After passing through the separation interface, the separated dust is discharged through the dust outlet.

3, Exhaust process

The process of relatively purified airflow being discharged from the exhaust port after dust removal

6Standards for Cartridge Dust Collectors

2002 Machinery Industry Standard of the People’s Republic of China: Standard for Cartridge Dust Collectors JB/T10341 -2002

Characteristics of the filter cartridge dust collector

①Because the filter material is pleated into a cylindrical shape, the density of the filter material is high, so the filter material is Compact structure and small volume;

②The height of the filter cartridge is small, the installation is convenient, and the use and maintenance workload is small;

③ The filter area of the dust collector with the same volume is relatively large, and the filtering wind speed is small , the resistance is not large;

④The pleats of the filter material should be tightly sealed at both ends, and there should be no air leakage, otherwise the effect will be reduced.

The characteristics of the pulse filter cartridge dust collector are as follows:

1. The filter cartridge adopts imported polyester fiber as the filter material, and a layer of sub-micron filter The ultra-thin fibers are adhered to the general filter material, and the fibers are arranged very closely on the adhesion layer, and the extremely small sieve holes can block most of the sub-micron dust particles on the surface of the filter material;

2. The use of pleated filter media can increase the filter area and make the dust collector more compact;

3. The height of the filter cartridge is small, and the installation and maintenance workload is small;

4. Compared with the dust collector of the same volume, the filter area is relatively large, the filtering wind speed is small, and the resistance is not large;

5. The single-machine dust collector adopts the pulse jet online dust cleaning method. . The cleaning process is automatically controlled by the pulse controller. Multiple filter cartridges are set in the dust collector to increase its effective filtering area. When a certain (pair) filter cartridge meets the set requirements for cleaning dust, the blowing device is started to clean the dust, and other filter cartridges work normally, which not only achieves the The cleaning effect does not affect the operation of the equipment, so that the dust collector can operate continuously; the combined dust collector adopts the automatic cycle cleaning of the offline pulse in the sub-chamber. Multiple filter cartridges are installed in each dust chamber to increase its effective filtering area. When a filter cartridge in a dust chamber meets the set requirements for cleaning dust, the blowing device is activated to clean the dust, and other dust chambers work normally, which not only ensures the The cleaning effect can also make the dust collector run continuously;

6. High dust removal efficiency (generally up to 99.6% or more), easy to operate;

Main performance indicators

The pulsed airflow is directly injected into the filter cartridge without passing through the venturi. This will cause one end (upper) of the filter cartridge close to the pulse valve to be under negative pressure, while the other end (lower) of the filter cartridge will be under pressure as shown in Figure 6-29. This will cause the upper and lower parts of the filter cartridge to be cleaned differently, which may shorten the service life and prevent the equipment from effectively cleaning the dust.

For this purpose, a Venturi nozzle for the filter cartridge can be installed on the outlet of the pulse valve or on the pulse jet line. The distribution of the injection pressure is improved to a relatively uniform high positive pressure injection of the full filter cartridge.

The accumulation of dust in the folded slits of the filter cartridge will make cleaning more difficult. Therefore, the filter cartridges with large folded area (each filter cartridge has a filtration area of 20~22m2) are generally only suitable for use in the case of lower inlet concentrations. Compare the common filter cartridge size and filter area.

The air distribution box of the pulse injection device of the filter cartridge dust collector shall comply with the regulations of JB/T 10191-2000. The clean air should be free of water, oil and dust. Under the specified conditions, the injection valve and the interface of the pulse valve should have no air leakage, and can be opened and closed normally, and the work is reliable.

The pulse controller should work accurately and reliably, and its injection time and interval can be adjusted within a certain range. When the induction blowing device is installed with the blowing pipe. The nozzle of the induced blowing device should be coaxial with the nozzle hole on the blowing pipe, and keep the same verticality with the nozzle, and the deviation should be less than 2mm.

Cartridge Dust Collector Cartridges and Media

Filter Cartridges

Cartridge Dust Removal The filter element of the filter is the filter cartridge. The structure of the filter cartridge is divided into four parts: the top cover, the metal frame, the pleated filter material and the base. The filter cartridges composed of these four parts are round, flat and conical.

The filter cartridge is folded into pleats with the filter material of the designed length, and the end and end are bonded into the cylinder. The top cover has fixing bolts and washers. Round filter cartridge, the shape of the flat filter cartridge.

The upper and lower end caps of the filter cartridge and the protective net should be bonded reliably, and there should be no defects such as degumming, glue leakage and sagging; the metal parts on the filter cartridge should meet the anti-rust requirements; The surface should be free from defects such as obvious scars, bumps, burrs and burrs; the filter cartridge can be sprayed and cleaned with an induction nozzle or a venturi and other spray devices as required, and a protective net should be installed on the inside of the filter cartridge. When D≥320mm is selected , H ≥ 1200mm filter cartridge, should be equipped with induction nozzle.

Commonly used filter cartridges are divided into three categories. The table shows the different protection objects and installation positions of different air filter cartridges

The volume of the finished filter cartridge has a great relationship with the volume of the filter assembly. The host using the filter assembly often puts forward the following requirements for the filter: ① the total height of the dust collector and the distance between the inlet and outlet (width); ② the total height and diameter of the lower body of the filter cartridge; ③ the total mass of the filter cartridge; ④ the connection method of the air outlet and ⑤ A series of performance requirements related to filtration characteristics such as filtration accuracy.

The filter cartridge design should pay attention to the following elements according to the assembly requirements

(l) The outer diameter of the filter cartridge should be more than 10mm larger than the inner diameter of the filter cartridge. This is because the high and narrow space allows the polluting particles to settle slowly on the outer layer of the filter cartridge, so that the filter cartridge is evenly blocked by pollution from top to bottom.

(2) In the determination of the diameter of the inner frame, the main consideration is that the size of the oil-passing holes should not affect the amount of filtered air, and at the same time, the influence of the size of the holes on the strength of the frame should be considered.

(3) The overall strength of the inner frame is extremely important. First of all, the pressure difference that the filter cartridge bears must be supported by the frame, so the smaller the diameter, the higher the strength.

(4) The height of folded and wrinkled teeth should be between l0~50mm.

(5) Leave enough room for the pressure difference limit. After calculating the required filtration product, the area should be doubled. This is because dust pollutants are unpredictable in actual work.

Filter Media

There are two types of filter media for filter cartridges: one is synthetic fiber filter media, and the other is paper filter media.

Synthetic nonwoven filter media. According to the processing technology, it can be divided into two categories: continuous fiber spunbond polyester hot pressing and short fiber spunbond polyester hot pressing. When the surface of the filter material is under the condition of waterproof treatment, the infiltration angle of the filter material after waterproof treatment should be greater than 90°, and the water level should not be lower than grade IV. When the filter material is under oil-proof treatment condition, the filter material should be treated with oil-proof treatment. Polyester non-woven filter material can withstand working temperature not lower than 120 ℃. For other special working conditions such as high temperature and high humidity, the selection of the material and structure of the filter cartridge should meet the application requirements.

Paper filter media can be divided into two types: low air permeability and high air permeability.

There are also synthetic fiber non-woven PTFE membrane filter media and paper PTFE membrane filter media.

Top 10 brands of vacuum cleaners>>